gitks/actor/handler.rs

use crate::actor::message::{
    GitNodeMessage, NodeHealth, ROLE_PRIMARY, ROLE_REPLICA, RefUpdateEvent, RouteDecision,
};
use crate::server::GitksService;
use async_trait::async_trait;
use ractor::pg;
use ractor::{Actor, ActorProcessingErr, ActorRef, SupervisionEvent};
use std::collections::HashMap;

#[derive(Clone)]
pub struct GitNodeActor {
    pub version: String,
    pub service: GitksService,
}

impl GitNodeActor {
    pub fn init(service: GitksService) -> Self {
        GitNodeActor {
            version: env!("CARGO_PKG_VERSION").to_string(),
            service,
        }
    }
}

pub struct RepoEntry {
    pub role: String,
    pub last_commit: String,
}

pub struct GitNodeArgs {
    pub storage_name: String,
    pub grpc_addr: String,
}

pub struct GitNodeState {
    storage_name: String,
    actor_name: String,
    grpc_addr: String,
    repos: HashMap<String, RepoEntry>,
}

#[async_trait]
impl Actor for GitNodeActor {
    type Msg = GitNodeMessage;
    type State = GitNodeState;
    type Arguments = GitNodeArgs;

    async fn pre_start(
        &self,
        myself: ActorRef<Self::Msg>,
        args: Self::Arguments,
    ) -> Result<Self::State, ActorProcessingErr> {
        let actor_name = format!("git_node_{}", args.storage_name);
        pg::join("gitks_nodes".to_string(), vec![myself.get_cell()]);
        pg::join_scoped(
            args.storage_name.clone(),
            "node".to_string(),
            vec![myself.get_cell()],
        );
        tracing::info!(storage_name = %args.storage_name, actor_name = %actor_name, grpc_addr = %args.grpc_addr, "GitNodeActor started");
        Ok(GitNodeState {
            storage_name: args.storage_name,
            actor_name,
            grpc_addr: args.grpc_addr,
            repos: HashMap::new(),
        })
    }

    async fn handle(
        &self,
        myself: ActorRef<Self::Msg>,
        message: Self::Msg,
        state: &mut Self::State,
    ) -> Result<(), ActorProcessingErr> {
        match message {
            GitNodeMessage::ScanAndRegister => {
                let repos = self.service.scan_all_repo()?;
                tracing::info!(storage_name = %state.storage_name, found = repos.len(), "scanning local repositories");
                for repo_path in repos {
                    let relative_path = repo_path
                        .strip_prefix(self.service.repo_prefix.to_string_lossy().as_ref())
                        .unwrap_or(&repo_path)
                        .trim_start_matches('/')
                        .to_string();
                    register_repo(&myself, state, relative_path);
                }
            }

            GitNodeMessage::RegisterRepository(header) => {
                register_repo(&myself, state, header.relative_path);
            }

            GitNodeMessage::RemoveRepository(header) => {
                state.repos.remove(&header.relative_path);
                tracing::info!(storage_name = %state.storage_name, relative_path = %header.relative_path, "repository route removed");
            }

            GitNodeMessage::RefUpdated(event) => {
                if let Some(entry) = state.repos.get(&event.relative_path)
                    && entry.role == ROLE_REPLICA
                {
                    let local_path = self.service.repo_prefix.join(&event.relative_path);
                    crate::actor::sync::sync_from_primary(event, local_path).await;
                }
            }

            GitNodeMessage::FindPrimary(header, reply) => {
                let entry = state.repos.get(&header.relative_path);
                let is_primary = entry.is_some_and(|e| e.role == ROLE_PRIMARY);
                reply
                    .send(build_decision(
                        state,
                        &header,
                        is_primary,
                        entry.map(|e| e.role.as_str()),
                    ))
                    .ok();
            }

            GitNodeMessage::FindReplica(header, reply) => {
                let entry = state.repos.get(&header.relative_path);
                let has = entry.is_some();
                reply
                    .send(build_decision(
                        state,
                        &header,
                        has,
                        entry.map(|e| e.role.as_str()),
                    ))
                    .ok();
            }

            GitNodeMessage::ListRepositoryPaths(reply) => {
                let paths: Vec<String> = state.repos.keys().cloned().collect();
                reply.send(paths.join("\n")).ok();
            }

            GitNodeMessage::RepositoryExists(header, reply) => {
                reply
                    .send(state.repos.contains_key(&header.relative_path))
                    .ok();
            }

            GitNodeMessage::GetNodeHealth(reply) => {
                reply
                    .send(NodeHealth {
                        storage_name: state.storage_name.clone(),
                        repo_count: state.repos.len() as u64,
                        healthy: true,
                        version: self.version.clone(),
                    })
                    .ok();
            }
        }
        Ok(())
    }

    async fn handle_supervisor_evt(
        &self,
        _myself: ActorRef<Self::Msg>,
        evt: SupervisionEvent,
        _state: &mut Self::State,
    ) -> Result<(), ActorProcessingErr> {
        match evt {
            SupervisionEvent::ActorStarted(who) => {
                tracing::debug!(actor = ?who.get_id(), "child started")
            }
            SupervisionEvent::ActorTerminated(who, _, reason) => {
                tracing::warn!(actor = ?who.get_id(), reason = ?reason, "child terminated")
            }
            SupervisionEvent::ActorFailed(who, panic_msg) => {
                tracing::error!(actor = ?who.get_id(), msg = %panic_msg, "child panicked")
            }
            SupervisionEvent::ProcessGroupChanged(group) => {
                tracing::info!(group = ?group, "PG membership changed")
            }
            _ => {}
        }
        Ok(())
    }

    async fn post_stop(
        &self,
        _myself: ActorRef<Self::Msg>,
        state: &mut Self::State,
    ) -> Result<(), ActorProcessingErr> {
        tracing::info!(storage_name = %state.storage_name, "GitNodeActor stopped");
        Ok(())
    }
}

fn build_decision(
    state: &GitNodeState,
    header: &crate::pb::RepositoryHeader,
    found: bool,
    role: Option<&str>,
) -> RouteDecision {
    RouteDecision {
        found,
        storage_name: if found {
            state.storage_name.clone()
        } else {
            String::new()
        },
        relative_path: header.relative_path.clone(),
        actor_name: if found {
            state.actor_name.clone()
        } else {
            String::new()
        },
        grpc_addr: if found {
            state.grpc_addr.clone()
        } else {
            String::new()
        },
        role: role.unwrap_or("").to_string(),
    }
}

fn register_repo(
    myself: &ActorRef<GitNodeMessage>,
    state: &mut GitNodeState,
    relative_path: String,
) {
    if state.repos.contains_key(&relative_path) {
        return;
    }

    // Determine role based on cluster state
    // For simplicity and correctness, we use a conservative approach:
    // If there are other nodes in the cluster, register as replica initially.
    // The route_repository logic will determine the actual primary at query time.
    let members = ractor::pg::get_members(&"gitks_nodes".to_string());
    let my_cell = myself.get_cell();
    let other_nodes_exist = members.iter().any(|m| m != &my_cell);

    let role = if other_nodes_exist {
        // Conservative: assume another node might be primary
        // The actual primary will be determined by route_repository query
        ROLE_REPLICA.to_string()
    } else {
        // We're the only node, so we're primary
        ROLE_PRIMARY.to_string()
    };

    let category = extract_category(&relative_path);
    pg::join_scoped(
        state.storage_name.clone(),
        category.to_string(),
        vec![myself.get_cell()],
    );
    state.repos.insert(
        relative_path.clone(),
        RepoEntry {
            role: role.clone(),
            last_commit: String::new(),
        },
    );
    tracing::info!(
        storage_name = %state.storage_name,
        category = %category,
        relative_path = %relative_path,
        actor_name = %state.actor_name,
        role = %role,
        "repository route registered (role will be refined at query time)"
    );
}

fn extract_category(relative_path: &str) -> &str {
    relative_path.split('/').next().unwrap_or("root")
}

pub async fn start_node_actor(
    service: GitksService,
    storage_name: String,
    grpc_addr: String,
) -> Result<(ActorRef<GitNodeMessage>, tokio::task::JoinHandle<()>), ractor::SpawnErr> {
    let actor = GitNodeActor::init(service);
    let (actor_ref, handle) = Actor::spawn(
        Some(format!("git_node_{storage_name}")),
        actor,
        GitNodeArgs {
            storage_name,
            grpc_addr,
        },
    )
    .await?;
    actor_ref.cast(GitNodeMessage::ScanAndRegister).ok();
    Ok((actor_ref, handle))
}

pub fn get_cluster_nodes(storage_name: &str) -> Vec<ractor::ActorCell> {
    pg::get_scoped_members(&storage_name.to_string(), &"node".to_string())
}

pub fn get_category_members(storage_name: &str, category: &str) -> Vec<ractor::ActorCell> {
    pg::get_scoped_members(&storage_name.to_string(), &category.to_string())
}

pub fn route_group_for(header: &crate::pb::RepositoryHeader) -> String {
    extract_category(&header.relative_path).to_string()
}

pub fn list_all_groups() -> Vec<String> {
    pg::which_groups()
}

pub fn broadcast_ref_update(_node_actor: &ActorRef<GitNodeMessage>, event: RefUpdateEvent) {
    let members = ractor::pg::get_members(&"gitks_nodes".to_string());
    for member in members {
        let actor_ref: ActorRef<GitNodeMessage> = member.into();
        actor_ref
            .cast(GitNodeMessage::RefUpdated(event.clone()))
            .ok();
    }
}